Methods and devices for estimating a loading state of a vehicle have already been known. For example, a method and a device for estimating a loading state of a vehicle are described in the under-mentioned patent citation 1, in which a relationship of phase difference between steering angle and yaw rate relative to steering angular velocity is predetermined and a loading state of a vehicle is estimated on the basis of a detected relationship of phase difference between steering angle and yaw rate relative to steering angular velocity and the predetermined relationship.